/**
 * IK 中文分词  版本 5.0
 * IK Analyzer release 5.0
 * 
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * 源代码由林良益(linliangyi2005@gmail.com)提供
 * 版权声明 2012，乌龙茶工作室
 * provided by Linliangyi and copyright 2012 by Oolong studio
 * 
 * 
 */
package org.wltea.analyzer.sample;

import java.nio.file.Paths;

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.StringField;
import org.apache.lucene.document.TextField;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.index.IndexWriterConfig.OpenMode;
import org.apache.lucene.queryparser.classic.QueryParser;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory;
import org.junit.Test;
import org.wltea.analyzer.lucene.IKAnalyzer;

/**
 * 使用IKAnalyzer进行Lucene索引和查询的演示
 * 
 * 以下是结合Lucene4.2.0 API的写法
 *
 */
public class LuceneIndexAndSearchDemo {

    /**
     * 模拟： 创建一个单条记录的索引，并对其进行搜索
     * 
     * @param args
     */
    @Test
    public void test() throws Exception {
        // Lucene Document的域名
        String fieldName = "text";
        // 检索内容
        String text = "IK Analyzer是一个结合词典分词和文法分词的中文分词开源工具包。它使用了全新的正向迭代最细粒度切分算法。";

        // 实例化IKAnalyzer分词器
        Analyzer analyzer = new IKAnalyzer(true);

        // 建立内存索引对象
        Directory directory = FSDirectory.open(Paths.get("_index"));

        // 配置IndexWriterConfig
        IndexWriterConfig iwConfig = new IndexWriterConfig(analyzer);
        iwConfig.setOpenMode(OpenMode.CREATE_OR_APPEND);
        IndexWriter iwriter = new IndexWriter(directory, iwConfig);
        // 写入索引
        Document doc = new Document();
        doc.add(new StringField("ID", "10000", Field.Store.YES));
        doc.add(new TextField(fieldName, text, Field.Store.YES));
        iwriter.addDocument(doc);
        iwriter.close();

        // 搜索过程**********************************
        // 实例化搜索器
        IndexReader ireader = DirectoryReader.open(directory);
        IndexSearcher isearcher = new IndexSearcher(ireader);

        String keyword = "中文分词工具包";
        // 使用QueryParser查询分析器构造Query对象
        QueryParser qp = new QueryParser(fieldName, analyzer);
        qp.setDefaultOperator(QueryParser.AND_OPERATOR);
        Query query = qp.parse(keyword);
        System.out.println("Query = " + query);

        // 搜索相似度最高的5条记录
        TopDocs topDocs = isearcher.search(query, 5);
        System.out.println("命中：" + topDocs.totalHits);
        // 输出结果
        ScoreDoc[] scoreDocs = topDocs.scoreDocs;
        for (int i = 0; i < topDocs.totalHits.value; i++) {
            Document targetDoc = isearcher.doc(scoreDocs[i].doc);
            System.out.println("内容：" + targetDoc.toString());
        }

        ireader.close();
        directory.close();
    }
}
